(Prefix) Reverse of or absence of
1. Not; other than; reverse of; absence of
2. Of little or no consequence; unimportant; worthless
3. Lacking the usual especially positive characteristics of the thing specified

ETYM Old Eng. not, noht, nought, naught, the same word as Eng. naught. Related to Naught.
(Homonym: knot, naught).
Negation of a word or group of words.